This application is for continued general support of the research activities of the Department of Molecular Biology & Virus Laboratory. In July 1978 there will be fourteen active faculty members and one emeritus professor in this research group, together with about forty postdoctoral research associates, forty predoctoral students, and about one hundred people in technical and clerical capacities. All faculty members are supported in part by state funds and all have research grants that support their individual research programs which are housed in assigned core space in Stanley Hall. However, all of the faculty also use facilities and staff personnel housed in common use space and such facilities and services have for eighteen years been partly supported by a general program grant, most recently as a Cancer Center. Continued support of the Cancer Center is requested because we believe the total research in Stanley Hall is substantially related to the national cancer program, that a Cancer grant is economically and spacewise the most efficient way to support general facilities and services, and that facilities and services shared under this arrangement foster valuable exchanges among participating researchers. The research in the Molecular Biology-Virus Laboratory Cancer Center includes such topics as the molecular biology of development employing Xenopus laevis and Drosophila melanogaster; gene regulation in eucaryotic cells (Tetrahymena) and procaryotic cells (E. coli and phases lambda and P2-P4); recombination mechanisms (E. coli); genetic structure and replication of DNA and RNA tumor viruses; structure and function of enzymes and other macromolecules; coordination of metabolism in normal and malignant cells; regulation of somatic cell growth and division; neuroembryological studies; mutagenesis and carcinogenesis.